Event adjudicator and interface

ABSTRACT

An event adjudicator (10) comprising a first event register (14) capable of registering the occurrence of each of a plurality of local events, a second event register (16) capable of registering the occurrence of one or more remote events, which local and remote events constitute a group of events, an adjudicator (12) capable of determining which event of the group of events occurred first and providing an output accordingly. An interface (16) comprising a sensor (V1, 20) arranged to sense an actuating signal from a television unit (66) and a controller (22, 24) to produce a control signal correspondent with the actuating signal.

DESCRIPTION

The present invention relates to an event adjudicator and interfaceparticularly envisaged for use in adjudicating which event of aplurality of events occurred first.

FIELD OF THE INVENTION

In general, adjudication of events has been restricted to local eventsoccuring in close proximity to each other. For example the events to beadjudicated could be the acuation of answer buttons by contestants in atelevision quiz program to register which contestant was first to answera passed question.

Such adjudication systems have not allowed for the inclusion of remoteevents occuring at a distance from any local events.

SUMMARY OF THE INVENTION

The present invention provides an event adjudicator and interfacecapable of adjudicating the occurance of local events and remote events.

In accordance with one aspect of the present invention there is providedan event adjudicator characterized in that it comprises a first eventregistering means capable of registering the occurrence of each of aplurality of local events, a second event registering means capable ofregistering the occurrence of one or more remote events, which local andremote events constitute a group of events, an adjudicator means capableof determining which event of the group of events occurred first andproviding an output accordingly.

Preferably, the second event registering means is capable of registeringremote events presented to the event adjudicator of the presentinvention by a communication system such as, for example, a televisionbroadcasing system, or a radio communication system, or a telephonesystem or the like. In such manner, events originating remotely of theevent adjudicator are termed remote events.

Preferably, the event adjudicator is arranged for use in conjunctionwith a television set that is capable of receiving a television programin which a contest in which speed in answering questions or the like iscrucial.

Contestants in the television program preferably register theirknowledge of the answer to a question with the second event registeringmeans as fast as possible in order to be the contestant given theopportunity to answer correctly the question in order to gain a prize orother valuable consideration.

In such an arrangement the contestants in the television quiz programconstitute the originators of the remote events.

Preferably, the local events are originated by contestants situatedlocally with respect to the event adjudicator of the present invention.The local contestants also register their knowledge of the answer to thequestions or the like with the first event registering means as fast aspossible in order to be the first local contestant or first contestantoverall to be registered.

Preferably, once one contestant has registered his knowledge of theanswer no other contestant may be registered.

Preferably, contestants register by actuating a switch or the like toprovide a representation to the first or the second event registeringmeans.

In accordance with a further aspect of the present invention there isprovided an interface comprising a sensor means arranged to receive anactuating signal from a television unit and means to produce a controlsignal correspondent with the actuating signal.

The present invention will hereinafter be described with particularreference to a quiz contest broadcast on a television network, althoughit is to be understood that it is of general applicability.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of example withreference to the accompanying drawings, in which:

FIG. 1 is a block diagram of an event adjudicator in accordance with thepresent invention;

FIG. 2 is a circuit diagram corresponding to the block diagram of FIG.1;

FIG. 3 is a timing diagram for the event adjudicator for the eventadjudicator of FIG. 2 for a serially transmitted data stream;

FIG. 4 is a block diagram of an enhanced event adjudicator similar tothat of FIGS. 1 and 2;

FIG. 5 is a block diagram of a data encoding a a distribuation systemfor use with the event adjudicator of FIGS. 1, 2 and 4; and

FIG. 6 is a block diagram of a data transmission/reception arrangementfor use with the event adjucicator of FIGS. 1, 2 and 4.

DESCRIPTION OF THE INVENTION

In FIG. 1 there is shown an event adjudicator 10, comprising anadjudicator means 12, a first event registering means 14 and a secondevent registering means 16.

The first event registering means 14 comprises a plurality of switches18, or the like actuators to register an event with the first eventregistering means 14, such as, for example, three switches 18.

The second event registering means 16 comprises a sensor means 20, apulse detector 22 and a missing pulse detector 24.

The sensor means 20 comprises a sensor V1 as shown in FIG. 2. The sensorV1 in the present embodiment is an optical type sensor such as aphototransistor, or more specifically, a darlington photo transistor,although it is envisaged that other optical sensors could be used.

The sensor V1 is housed in a mounting means (not shown) such as asuction cap. The sensor V1 is intended to be, in use, detachably fixedto a television screen. The sensor V1 is arranged, in use, to detect achange in the luminance of a portion of the television screen at whichit is fixed.

The area of the television screen at which the sensor V1 is located ishereinafter referred to as a box, of the television screen. The width ofthe box is preferably of an order similar to the width of a line of thetelevision screen as generated by an electron beam although it is to beunderstood that the box could have a width corresponding with more thanone line of the television screen.

When the luminance in the box is low, indicating an absence of colour,such as when it is black, the sensor V1 provides a representation of afirst condition.

Preferably, absence of colour is any signal in the box with a luminancecomponent of less than 500 mV peak to peak with respect to synctip wherea white level is measured as 1 V with respect to the synctip and blacklevel is 300 mV with respect to synctip.

More preferably, absence of colour is any signal in the box with aluminance component of not more than 300 mV. When the luminance in thebox is high, indicating a presence of colour, such as when it is white,the sensor V1 provides a representation of a second condition.Preferably presence of colour is any signal in the box with a luminancecomponent greater than 700 mV.

Preferably, the detection of the colour by the sensor V1 issubstantially independent of the hue or level of saturation of thesignal in the box.

Preferably, the first condition corresponds to an inactive OFF state andthe second condition corresponds to an active ON state.

The pulse detector 22 comprises a D-type flip flop V3 and an RS latchV7, V8 configured to produce an output at pin D4 of a D-type flip flopV9 of the adjudicator means 12. A clock input C of the flip flop V3 isdriven by the sensor V1. The box of the television screen is scanned byan electron beam of the television, for example, once every 20 ms for aPAL system operating on 50 Hz.

Thus, if colour is present in the box the clock input C will have apulse wave voltage of a period of 20 ms. Accordingly, while a resetinput R of the flip flop V3 is inactive an output Q of the flip flop V3will also have a voltage that is a pulse wave with the period of 20 mscorresponding to that of the clock input C.

In such a condition the pulse detector 22 detects that there is anactivating signal present on the television screen adjacent the sensorV1 and alerts the adjudicator 12 accordingly.

The output Q of the flip flop V3 is connected to a reset combinationcomprising a capacitor C1, a resistor R2 and a diode V2. The capacitorC1 and the resistor R2 have such value as to have a time constant ofapproximately half of the period of the voltage waveform at the clock Cand preferably half the field rate of the television. That is the timeconstant R2C1 is approximately 10 ms for the exemplary PAL system. Sucha value is preferable to ensure that the flip flop V3 is reset everycycle of the clock C input so as to be ready to detect the luminance ofthe box for each field. The flip flop V3 is reset when the voltage ofthe reset R exceeds about half of the supply voltage, that is about 4.5volts for a supply voltage of 9 volts.

Once the flip flop V3 is reset the voltage at the output Q goes low andthe capacitor C1 is rapidly discharged via the diode V2.

The flip flop V3 is now ready to be clocked by the next scan of theelectron beam, provided there is still a presence of colour in the box.

The RS latch V7, V8 produces a stable high output at the pin D4 of theflip flop V9 in response to the 20 ms period square wave at the outputQ. That is, the RS latch V7, V8 produces a high output when the box isilluminated.

The flip flop V3 also comprises a Q output which is connected to themissing pulse detector 24. The output Q is connected to a clockcombination comprising a capacitor C2, a resitor R3 and a diode V4.

The missing pulse detector 24 also comprises a D-type flip flop V5having a clock input 24C, a reset input 24R and an output 24Q.

When the voltage at the output Q is low the voltage at the output Q ishigh and the capacitor C2 changes up via the resistor R3. The timeconstant of the capacitor C2, resistor R3 combination is preferably suchthat when the output Q remains low for greater than 10 ms, that is, whenthe box changes to the first state having an absence of colour, thecapacitor C2 provides a logical high to the clock input 24C of the flipflop V5. The logical high at the clock input 24C produces a logical highat the output 24Q, which output resets the RS latch V7, V8 and thuspresents a logical low to pin D4.

Simultaneously, the output 24Q of the missing pulse detector 24 sets theoutput of the NOR gate V19 to a low voltage and enables the flip flopV9, which now has all D inputs at a low voltage, and thus resets theadjudicator means 12.

The missing pulse detector 24 accordingly detects the absence of theactivating signal at the sensor V1 and alerts the adjudicator means 12accordingly.

Where the activating signal provides a visible base the time delay indetecting a transition to an OFF condition is quite long and it has beenfound that the time constant C2 R3 is preferably at least 500 ms toensure that little or no false resetting of the RS latch V7, V8 mayoccur.

However, it has been found that where it is acceptable to have anactivating signal which is not visible the box can be activated anddeactivated at the field rate, that is at 50 Hz for a PAL system ascompared to 3.81 Hz where visibility is desired. In such a case the timeconstant C2 and R3 may be set to about 15 ms, leaving a 5 ms errormargin.

Where the output Q has a square wave voltage on it the capacitor C2 isdischarged via the diode V4 once every scan of the television screen.

The flip flop V5, similarly to the flip flop V3, has a reset combinationcomprising a capacitor C3, a resistor R4 and a diode V6. The combinationhas a similar function to that associated with the flip flop V3. Thecapacitor C3 and the resistor R4 preferably have a time constant of suchlength as to provide an automatic reset function as describedhereinafter.

It has been found that a time constant equal to that of time constantC1R2 is suitable, that is about 10 ms, so that where the capacitor C2 isallowed to charge for only about 10 ms the output 24Q is kept low andthe capacitor C3 not allowed to charge up thus indicating that the boxis still ON.

Where capacitor C2 is allowed to charge up for greater than about 15 msthe missing pulse detector 24 is triggered and the output 24Q is sethigh. That is when the box goes from an illuminated condition to anon-illuminated condition the output 24Q generates a reset pulse whichrepresents to the adjudicator means 12 that the box has entered thefirst inactive OFF state. Then the capacitor C3 begins to change via R4to reset the flip flop V5 and set the output 24Q to a low ready forfurther detecting.

The second event registering means 16 is in effect an interface betweenthe television screen and the adjudicator means 12. The interface allowsfor the activation of a remote unit, such as, for example, theadjudicator, by an activating signal transmitted in a video transmissionsignal.

The interface may also be used to transfer data from, for example, atelevision broadcast studio to a remote unit linked by the interface toa television screen as described hereinafter.

The adjudicator 12 comprises a filter arrangement formed of resistors R5to R10 and capacitors C4-C6. The filter arrangement connects theswitches 18 of the first event registering means 14 to the flip flop V9.Switches S1, S2 and S3 are respectively connected via the filterarrangement to inputs D1, D2, and D3 of the flip flop V9.

The filter arrangement is intended to AC couple the switches 18 to theflip flop V9 so that closure of one or more of the switches 18 resultsin a relatively short voltage pulse at the respective input D1, D2 orD3. Such a short voltage pulse is preferred to register an event withthe flip flop V9 of the adjudicator means 12. If such a filterarrangement were not incorporated a contestant may be able to jam theadjudicator means 12 by not releasing his or her switch 18.

The flip flop V9 also comprises outputs Q1 to Q4 and an enable input E.The outputs Q1 to Q3 correspond to the inputs D1 to D3 and the switchesS1 to S3, respectively and thus to the local contestants. The output Q4corresponds to the input D4 and the senor V1 and thus to the remotecontestant.

The adjudicator means 12 will accept logical high signals at the inputsD1 to D4 and respectively produce logical high signals at the outputs Q1to Q4 provided the enable input E is set, that is, has a logical lowvoltage.

When the enable input E has a logical high voltage none of the inputs D1to D4 are accepted and the present output status of the flip flop V9 ismaintained.

The adjudicator means 12 also comprises two NOR gates V18 and V19. TheNOR gate V18 has inputs preferably connected to the outputs Q1 to Q3.

The NOR gate V19 has inputs connected to the output of the NOR gate V18,the output 24Q of the second event registering means 16 and a manualreset means 26.

The NOR gates V18 and V19 serve to disable the flip flop V9 when thefirst one of the contestants registers his/her answer.

When any of the switches S1 to S3 is actuated, or the remote contestantsactuate a similar switch (not shown) the first switch registered isreceived by the flip flop V9 and the corresponding output Q1 to Q4 goesto a logical high. The high output produces a low output at the NOR gateV18 and a high output at NOR gate V19. The NOR gate V19 output then setsa high voltage at the enable input E and thus disables the inputs D1 toD4. Thus, once one local switch 18 closure is received by theadjudicator means 12 all other switch closures are disregarded by theflip flop V9.

Where the remote contestant is first to be registered the flip flop V9will set the output Q4 high and will wait for the first local contstantto also register an answer.

It is envisaged that the inputs of the NOR gate V18 could include aconnection to the output Q4. Thus, the first contestant whether local orremote registered, will disable the inputs D1 to D4 of the flip flop V9.The outputs Q1 and Q4 are connected to a display means 28. The displaymeans 28 comprises LED's V11, V13, V15 and V17 connected to be lit whena corresponding output occurs.

The activating signal may be coded in order to allow data transmissionfrom a television broadcast station to the event adjudicator 10. Thedata may be either coded serially or in parallel.

In the latter case a plurality of second event registering means 16corresponding to the number of bits in parallel coded data and anyparity bits.

In the former case a simple second event registering means 16 may beused and having its output connected to a Universal AsynchronousReceiver and Transmitter (UART) 50 shown incorporated with theadjudicator means 12 in FIG. 4 and also shown in the datatransmission/reception arrangement of FIG. 6.

The UART 50 is operated in conventional manner to receive data bits fromthe second event registering means 16 and converting them to a parallelword for display, on a display means 28a, and the like.

In FIG. 3 there are shown waveform diagrams for the reception of thedata word 6B Hex (1101011 binary).

The waveforms in FIG. 3 represent (a) internal transmit clock for anencoder UART 52 (FIG. 6) present at the television broadcasting station,(b) television screen data stream appearing at the sensor V1 during aperiod of time, (c) signal appearing at the clock input C of flip flopV3, (d) and (e) Q and Q outputs of flip flop V3, (f) clock input 24C atflip flop V5 (the dashed line representing trigger level), (g) resetpulse from missing pulse detector 24, (h) output from RS latch V7, V8 tothe UART 50 and (i) internal receive clock for the UART 50.

In FIG. 6 there is shown a data transmission unit 53 for use with theapparatus 10 of the present invention. The transmission unit 53comprises the encoder UART 52 is connected, for example, to a keyboard54 via an encoder 56 and having a parallel input port 57 with anexternal clock generator 58. The UART 52 has a serial output port 60which is connected to a pattern generator 62 configured to generate theabove mentioned base.

The pattern generator 62 has an output 64 which is arranged to bebroadcast or closed circuit transmitted to a television unit 66. Thetelevision unit 66 may be located locally to the transmission unit 53 orremotely, such as in a closed circuit therein network, or a televisionbroadcast area or a satellite transmission zone or the like.

The television unit 66 displays the box as described hereinabove and astart bit SA followed by data bits D0 to D6, a parity bit and two stopbits so appear therein (FIG. 3b).

The sensor V1 sensors the and produces a series of pulses which appearat the clock input C as shown in FIG. 3c resulting in outputs Q and Q asshown in FIGS. 3d and 3e.

Where the output Q remains low for greater than about 15 ms the voltagerise at capacitor C2 (FIG. 3f) exceeds the trigger level and the missingpulse detector 24 is activated to reset the RS latch V7, V8 and apply alow signal to serial input 50a of the UART 50 under direction of areceive clock 68 having the same frequency as the transmit clock 58.

When all the start, data, priority and stop bits are accumulated by theUART 50 and the parity checked for data integrity the data is output atparallel output port 50b to the display 28a.

In FIG. 4 there is shown an enhanced event adjudicator 10 having bothdata reception and display and remote event adjudication. The eventadjudicator 10 also comprises, in the enhanced form, a score means 70 tokeep a tally of scores awarded for correct answers provided by acontestant found to be the first to register with the adjudicator means12. The score means comprises a score encoder 72 driven by theadjudicator 12, a score display 74 and a local adjudicator 76 to adjustthe scores in accordance with the correctness of the answer to the quizquestion.

The event adjudicator 10 may also comprise a record means 78 having adata encoder 80 to encode the score and the identity of thecorresponding contestant to be recorded, a printer 82 to provide a hardcopy of the score, and a data output means 84 for interface to acomputer or the like.

In FIG. 5 there is shown a data encoding and distribution system 90 alsosuitable for use with the event adjudicator 10 of the present invention.The system 90 comprises a background video signal generator 92, a keysignal means 94, a key controller 96, a video keyer 98 and a videorecord/transmission network 100.

The background video signal generator 92 may comprise a conventionalvision mixer 92a, video tape recorder 92b, tuner 92c, computer 92d or atelevision camera 92e or the like, used to control the composite videosignal forming the background of a screen video signal at the videokeyer 98.

The key signal means 94 comprises a key source 94a configured to directwhere and when the video keyer 98 is to cut the box in the backgroundvideo signal. The key signal means 94 also comprise a key fill I 94b anda key fill II 94c configured to direct the vision mixer 92a to fill thebox with a high luminance signal (white) and a low luminance signal(black) respectively. The key controller 96 comprises a computer 96a anda televisiion quiz show 96b. The key controller 96 controls which of thekey fills 94b or 94c fill the box cut in the background video signal.Also the key controller 96 is arranged to provide field synchronisedswitching signals to the video keyer 98 when data is to be transmitted.

It is envisaged that data to be transmitted could comprise answers tothe quiz questions transmitted either before the commencement of thequiz and stored in the event adjudicator 10 or transmitted as anannouncer calls the question.

The video record-transmission network 100 comprises, for example, atelevision broadcast system 100a, a satellite system 100b, a closedcircuit television system 100c, a cable television network 100d, a videotape recorder 100e and/or a television 100f.

It is envisaged that the key source 94a could be a Chroma, R.G.B. orMatt key signal developed by a colour or monochrome television camera.

Also, it is envisaged that the box could be superimposed using a frameaccurate edit system such as a computer aided video tape edit system.

In use, the event adjudicator 10 of the present invention is arranged inconjunction with a communication medium such as shown in FIGS. 5 and 6.The event adjudicator 10 adjudicates a contest between localcontestants, for example, contestants in a home, with respect to aremote contestant, for example a group of contestants in a contestbroadcast over a television broadcasting system or the like.

The contest is broadcast with information relating to the actuation ofswitches, or the like, used by the remote contestants to register ananswer to a question, such as a question in a quiz television program.

Preferably, the information is broadcast as a small box on thetelevision screen that can be illuminated or darkened independently ofthe remainder of the television picture.

Preferably, the location of the box on the screen is fixed so that inuse, the sensor V1 can be fixed to the television screen adjacent thebox.

It is intended that when a remote contestant actuates a switch to answera question there is simultaneously broadcast a signal of high luminance(greater than 700 mV) to correspond with the box fixed to the televisionscreen.

The highly luminous signal corresponding to the box is detected by thesensor V1. The sensor V1 produces a voltage at its output, which voltagetriggers the second event registering means 16.

The second event registering means 16 then provides an active output tothe adjudicator means 12.

When the luminance content of the signal in the box is high the secondevent registering means 16 indicates to the adjudicator means 12 that aremote contestant has actuated his/her switch or that a contest time outis in progress. Meanwhile, a local contestant having received thequestion at the same time as the remote contestants via the televisionbroadcast may also attempt to register with the first event registeringmeans 14 by actuating his switch S1, S2 or S3. When one of the switchesS1, S2 or S3 is actuated a voltage pulse appears at a correspondinginput D1, D2 or D3 at the flip flop V9 via the filter arrangement.

Provided the flip flop V9 is enabled the flip flop V9 will accept thesignal at its inputs D1 to D4 and produce an output. The output produceddepends on which input receives a signal first.

If, one of inputs D1 to D3 register the first signal a correspondingoutput Q1 to Q3 goes logically high, a corresponding LED V11, V13 or V15is illuminated and NOR gates V18 and V19 operate to disable the inputsof the flip flop V9.

Thus, if one of the local contestants is first to be registered theadjudicator means acts to disregard subsequent input signals from theregistering means 14 or 16.

If one of the remote contestants is registered first the output Q4becomes logically high and the LED V17 of the display means 28 isilluminated. The flip flop V9 is then reset by closure of a reset switchS4 or S5 of the reset means 26 or by the missing pulse detector 24 asdescribed hereinabove.

Once one question has been answered the flip flop V9 is either reset bythe missing pulse detector 24, as described hereinabove or by the resetmeans 26.

It is envisaged that the remote contestants could be a plurality ofgroups of remote contestants, in which case a corresponding plurality ofsensors and boxes spaced about the television screen could be used. Itis envisaged that an adjustable time delay means be provided tocompensate for time lapsed in communication of the remote contestantsswitch actuation.

It is also envisaged that the second registering means 16 could besensitive to an audio signal transmitted by the broadcasting televisionstation and received by the television.

It is further envisaged that information relating to the box could betransmitted by a television broadcasting station as a page of teletext,in particular a caption page of teletext. In such manner, a televisionreceiver with a teletext decoder could be used to receive theinformation relating to the box. Thus, the coded teletext informationcould be used to trigger the second event registering means 16.

It is still further envisaged that coded information relating to the boxcould be presented at a television receiver in the vertical intervalblock of the television screen.

It is still further envisaged that the event adjudicator 10 of thepresent invention could be used in relation with a pre-recorded videoprogram such as a video program recorded on a video cassette and playedback on a video cassette recorder/player.

Modifications and variations such as would be apparent to a skilledaddressee are deemed wtihin the scope of the present invention. Forexampe, the event adjudicator 10 could be adapted to allow for anynumber of local or remote contestants. Also the event adjudicator 10could be used by only local contestants.

I claim:
 1. An event adjudicator for adjudicating which event of aplurality of local and remote events occurred first, such as in atelevision quiz program, the event adjudicator comprising:(a) a firstevent registering means having a plurality of switches disposed to beactuated by participants to register the local events; (b) at least onesecond event registering means for registering the remote events andhaving:(i) an optical type sensor means arranged to be detachablyattached to a television screen of a television unit to detect changesin the luminance of a portion thereof associated with the remote events;(ii) a pulse detector connected to the sensor means to detect changes inthe luminance of said portion, the pulse details having at an output anactive signal when the sensor means detected high luminance; (iii) amissing pulse detector connected to the pulse detector, the missingpulse detector having at an output an active signal when the sensormeans detects low luminance for a continuous period of time greater thanhalf the period of the field rate of the television unit, the missingpulse detector being connected to the pulse detector to reset same uponsuch detection of low luminance; (c) an adjudicator means having:(i) anedge triggered flip flop having a plurality of inputs and outputs inequal numbers, one of said inputs being connected to the output of thepulse detector of the corresponding one of the or each second eventregistering means to adjudicate the or each remote event; (ii) aplurality of filter means connected between said switches and theremainder of said inputs to AC couple said inputs to convert theregistered local events into short duration electrical signal toadjudicate said local events and (iii) a logic gate connected to atleast said outputs corresponding to said switches, the logic gate beingconnected to inhibit the edge triggered flip flop upon the occurrence ofone of the local events; and d. a display means connected to each of thesaid outputs to indicate when said outputs become active.
 2. An eventadjudicator according to claim 1, in which the output of the missingpulse detector is also connected to reset said edge triggered flip flopat detection of low luminance by the sensor means for a period greaterthan about half of the period of said field rate.
 3. An eventadjudicator according to claim 1, in which the pulse detector comprisesa reset combination to enable detection of the luminance of the portionfor each field of a picture of the television unit.
 4. An eventadjudicator according to claim 1, comprising a plurality of said sensormeans configured to sense an encoded video actuating signals at aplurality of said portions, and a decoder means to decode the sensedvideo actuating signals.
 5. An event adjudicator according to claim 1,in which the sensor means is configured to sense a video signal producedfrom a page or caption of teletext decoded by a teletext decoder of thetelevision unit.
 6. An event adjudicator according to claim 1, in whichthe sensor means is configured to sense a video signal produced in thevertical interval block of the screen of the television unit.
 7. Anevent adjudicator for adjudicating which event of a plurality of localand remote events occurred first, such as in a television quiz program,the event adjudicator comprising:(a) a first event registering meanshaving a plurality of switches disposed to be actuated by participantsto register the local events; (b) at least one second event registeringmeans for registering the remote events and having:(i) an optical typesensor means arranged to be detachably attached to a television screenof a television unit to detect changes in the luminance of a portion ofsaid television screen to produce an electrical signal correspondingthereto, the changes in luminance being associated with a videoactuating signal received by the television unit in a television signal;(ii) a pulse detector having an edge triggered flip flop connected tothe sensor means to detect the electrical signal corresponding to thevideo actuating signal, a reset combination configured to reset anoutput of the edge triggered flip flop at about half the period of thefield rate of the television unit to allow for detection of saidelectrical signal for each field of a picture of the television unit,and an electronic latch means connected to said output to provide anactive signal at its output upon detection of high luminance by thesensor means to register remote events; and (iii) a missing pulsedetector having a further edge triggered flip flop connected to thepulse detector via a RC timing circuit, the RC timing circuit beingconfigured to trigger the further edge triggered flip flop when theoutput of said edge triggered flip flop remains inactive for greaterthan about half the period of the field rate to provide an active signalat its output upon detection of low luminance by the sensor means toreset the electronic latch means, and a further reset combinationconfigured to reset the further edge triggered flip flop at about thehalf the period of the field rate of the television unit to reset thefurther edge triggered flip flop upon such detection of low luminance;(c) an adjudicator means having:(i) a still further edge triggered flipflop having a plurality of inputs and outputs in equal number, one ofsaid inputs being connected to the output of the electronic latch meansof a corresponding one of the or each second event registering means toadjudicate the or each remote event; (ii) a plurality of filter meanscorresponding in number with the plurality of switches of the firstevent registering means and connected between said switches and theremainder of said plurality of inputs, each filter means beingconfigured to provide AC coupling to convert the registered local eventsinto short duration electrical signals to adjudicate same; and (d) adisplay means connected to each output of the still further edgetriggered flip flop to indicate when same became active;the output ofthe missing pulse detector also being connected to reset said stillfurther edge triggered flip flop at detection of low luminance by thesensor means for a period greater than about half the period of saidfield rate.